THE 1-G SPACESHIP

[flaugher]

Question: What would be the Holy Grail of inter-planetary space flight? In my mind it would be an engine that could deliver forward thrust of 32 ft/sec/sec over a long time. In other words, a 1-G spaceship. I've been playing with this idea with Orbiter for awhile now and have come up with some intersting results: 4 days to Mars, 17 days home from Rhea. What's more, you can stand up in your ship, drink Tang from a glass, and flush the toilet. Is this really so far fetched considering the ground we've covered recently with ion engines? I hear that 10 ft/sec/sec has actually been achileved.

An easy way to try this principle out is start from Lunar orbit, point just to the side of Earth, and use the Accelerometer MFD and set your thrust for something around 9.5 meters/s/s. Use Earth in the Orbit MFD to check your distance (altitude) and turn your ship around when you get halfway home. I was totally shocked at the times and speeds involved.

On my way back from Rhea the other day, I hit the halfway point to Earth where I reverse the thrusters on my Firefly Sport, and I found that I was clipping along at over 3.7 million meters per second! Gosh! :yes:

Nowadays I'm looking for a good MFD to navigate considering constant acceleration and decelration.

 

[Artlav]

Is this really so far fetched considering the ground we've covered recently with ion engines? I hear that 10 ft/sec/sec has actually been achileved.

Very far-fetched, unfortunately.
Ion engines are just not the type for that kind of flights - despite being able to work for years, the thrust is negligible (idiomatic, not really).

What we need to make it true is some form of controlled fusion heater and universal exhaust reflector, or a nice way of producing lots of antimatter.
Neither is past theoretical abstractions yet.

Brachistochronal flights (that's how it's called, if i spelled it right) is indeed the fastest way to get from point A to point B in space, unless someone invents a practical teleport.

 

[joiz]

an orion type vehicle with little fusion pellets that you dump out the rear and fry with a laser, creating thrust. yes?

 

[yagni01]

Nowadays I'm looking for a good MFD to navigate considering constant acceleration and decelration.

Check Orbit Hanger for something called AGMFD

 

[RisingFury]

Currently, VASIMR is looking the best for deep space missions... but it produces faaaaar from 1G. The only thing we have right now that produces thrust in the G ranges are chemical rocket engines... but you're probably aware of their drawbacks.


Even if we had a very efficient engine that would be capable of providing high thrust, it would still take a big load of fuel...


The thing is though... why would you even bother going to Mars at 1G if you get there in 4 days? It's not like 4 days of microgravity will cause problems for the human body, but it would be soooo much more difficult to make your transportation system and much more costly.

If you are concerned about the time you spend at microgravity, you just build a more powerful rocket to shoot you out faster and shorten the trip.

 

[flaugher]

Sure, you could do that, but then you'd have to have a lot of fuel on board to slow you down once you got there. One nice thing about a Holmann transfer is that if you have engine problems on the way (witness Apollo 13) you just let the loop bring you on around and back home. Not that I like Holmann transfers because my whole point here is to find a way to avoid the things.

My hope is that NASA or whoever will continue to put a high priority on efficient thrusting, which I guess is the point of Deep Space 1 and 2. It's true that what we're waiting for here is a breakthorugh, so maybe one of the fusion projects will bring us something soon. For all the things I think Global Warming is not :lol: at least it HAS energized the climate studies community. Maybe a good energy crisis will do the same for spaceflight.

I think that this it is indeed a goal that we are reaching for, cheap efficient spaceflight, and I suspect it is also one that we will eventually reach, although it may involve waiting for other technologies too :blink:. When however we do have efficient 1-G engines at low cost (hopefully), then surely space travel will explode.

---------- Post added at 08:35 PM ---------- Previous post was at 08:18 PM ----------

Yes! Yes! AGMFD is exactly what I was looking for. Don't know why I overlooked it at the Hangar. This is great. Thanks. :lol:

 

[RisingFury]

All Apollo missions were set up to be on a free return trajectory, but it's not like you just fire your engines and you'll definitely return...

I think a 1G travel is quite unlikely to happen simply because of the amount of fuel you'd have to bring on your journey. Interstellar concepts like buzzard ramjet seem to be the most likely right now because they collect their fuel along the way and don't need to haul it with them.

But don't hold your breath on any sort of fusion drive or interstellar flight. Me and you will probably be 6 feet under a long time before it happens.

The other option is, of course, if we discover some way to fold the three dimensions we as humans are aware of through the higher dimensions and start making wormholes...... but so far nothing.

 

[Hielor]

The other option is, of course, if we discover some way to fold the three dimensions we as humans are aware of through the higher dimensions and start making wormholes...... but so far nothing.

Three-dimensional fingers can easily fold a two-dimensional shape through the third dimension to create a "wormhole."

All we need to create wormholes usable for travel, then, is some four-dimensional fingers.

 

[RisingFury]

Three-dimensional fingers can easily fold a two-dimensional shape through the third dimension to create a "wormhole."

All we need to create wormholes usable for travel, then, is some four-dimensional fingers.

You can use many explanations to try and imagine higher dimensions, but currently they're still theory... and we have no idea how to fold our 3 dimensional world through the 4th dimension...

Part of the problem may be that down here in the 3rd dimension, we're unaware of our movement in the dimensions above.

 

[mjl1966]

Even if we get 1G thrust, doesn't a "G" get larger as you go faster due to relativity? Sepcifically, the faster you go, the more mass you accumulate, thus the more thrust required to maintain 1 G of acceleration (which is proportional to mass).

Of course, distance gets shorter, too, wo maybe the two cancel each other out.

 

[Tommy]

The ship would need to create 9.5 m/s/s relative to itself. Since time would be passing "faster" for an "observer" than for a "passenger" , it would appear to the "observer that the acceleration diminished as the velocity increased, but to a "passenger" the acceleration would remain constant (provided the vessels engines could produce an ISP (or equivalant) fast enough to produce that acceleration)

 

[Hielor]

The ship would need to create 9.8 m/s/s relative to itself....

FTFY

 

[Jarvitä]

Even if we get 1G thrust, doesn't a "G" get larger as you go faster due to relativity? Sepcifically, the faster you go, the more mass you accumulate, thus the more thrust required to maintain 1 G of acceleration (which is proportional to mass).

Of course, distance gets shorter, too, wo maybe the two cancel each other out.

The relativity change factor (factor of mass increase, contraction in the direction of travel and time dilation) is 1.001 (where 1 means no change) when you reach the velocity of 13397 kilometres per second. That is, thirteen million metres per second. A factor of 2 occurs at 0.86c. Needless to say, even with constant 1g thrust, such velocities would not be reached when traveling within our solar system. Even if some calculations on the part of avionics and navigation systems might have to be made to account for the near-negligible-but-not-quite effects of relativity, the practically observable effect would be zero.

And, don't forget, even within the solar system, such a spacecraft wouldn't even be accelerating all the way. It needs to turn around and brake once it reaches the half of it's path, otherwise it won't be able to stop at the destination.

 

[Hielor]

And, don't forget, even within the solar system, such a spacecraft wouldn't even be accelerating all the way. It needs to turn around and brake once it reaches the half of it's path, otherwise it won't be able to stop at the destination.

Lithobraking!

 

[Artlav]

Lithobraking!

At such speeds?
You mean, planet busting?

 

[flaugher]

OK, ok. I see a lot of people's points, but sitting here in my office I just hears them talking on "The Tube" about the future of NASA, and whether or not there will BE one once we retire the shuttle fleet. I think I got started on this whole 1-G thing with the idea that it would be something we might be able to achieve, if we put our collective minds to it, that would really energize space travel again ... or at least the HOPE for it might ignite the public's fervor. None of us here needs a reason for NASA or survive. The unwashed masses and their elected officials certainly do.

 

[Wolfer]

Originally Posted by flaugher
What's more, you can stand up in your ship, drink Tang from a glass, and flush the toilet.

You would also need to have microgravity facilities once you reach your targeted planet's orbit, which would add to the overal weight of the spacecraft. Making it even less fuel eficient.

 

[dougkeenan]

You would also need to have microgravity facilities once you reach your targeted planet's orbit, which would add to the overal weight of the spacecraft. Making it even less fuel eficient.

Fuel efficiency has little to do with this method of travel.

 

[joiz]

You would also need to have microgravity facilities once you reach your targeted planet's orbit, which would add to the overal weight of the spacecraft. Making it even less fuel eficient.

nah, have a rotating station to dock to, you can live a few hours without drinking or peeing.

 

[T.Neo]

nah, have a rotating station to dock to, you can live a few hours without drinking or peeing.

Um, or you could have toilets and drinking recepticals that can be adapted to either 1 or zero G?